Abstract: Syntheses for the new multidentate chelating ligands ((6,6'-((1,4-diazepane-1,4-diyl)bis(methylene))bis(pyridine-6,2-diyl))bis(methy lene))bis(diphenylphosphine oxide) (2) and 6,6'-((1,4-diazepane-1,4-diyl)bis(methylene))bis(2-((diphenylphosphoryl)methyl) pyridine 1-oxide) (3), based upon a 1,4-diazepane platform functionalized with 2-(diphenylphosphinoylmethyl)pyridine P-oxide and 2-(diphenylphosphinoylmethyl)pyridine N,P-dioxide fragments, resp., are reported. Results from the coordination chem. of the ligands with selected lanthanide nitrates and Cu(BF4)2 are outlined, and crystal structures for two complexes, [Cu(2)](BF4)2 and [Cu(3)](BF4)2, are described along with survey Eu(III) and Am(III) solvent extn. anal., for 3. [on SciFinder(R)]